posted 08-12-2009 05:29 PM
In photographs of Neil Armstrong walking down the corridor of the Manned Spacecraft Operations Building and out into the transfer van on the morning of the Apollo 11 launch, the hoses leading from his portable ventilator to the pressure garment assembly (PGA) are clad in white cloth. An automatic photo taken of him crossing swing arm 9 to the white room a short time later shows the hoses to have changed, being black with strips of white tape at various places.

It appears at some stage between the transfer van and the white room his ventilator (or at least the hoses) was/were changed.

Walt Cunningham in his book mentions that he had to have a ventilator change prior to ingress into Apollo 7, and that he and the technician were reluctant to do so due to the concern of contaminating the pure oxygen atmosphere of the PGA - which makes me wonder if it was a common thing to do.

Does anyone know why Armstrong's ventilator was changed, and was this a normal process for them to use multiple ventilators between the suit room and getting into the space craft?

Perhaps because each unit could only provide oxygen for a limited amount of time, at least two sets of units were used sequentially from the time that the crew started breathing pure oxygen in the suiting room until they were hooked up to spacecraft oxygen. Journal Contributor James Hill calls attention to the fact that, as can be seen in launch-day photo 69-H-1121, units with white hoses were in use as they boarded the transfer van for the trip to the pad and, as can be seen in launch-day photo KSC-69PC-399, by the time they were on the swing arm, they were using black-hose units... We do not currently know if there was a thermal reason for using two different units or if the units could provide oxygen for less than the hour that the crews typically used the POVs and the difference in the hoses was a means of keeping track of the units.

The ALSJ also notes that the astronauts removed their helmets in the transfer van, so contaminating PGA's oxygen environment did not seem to be a concern by Apollo 11.

I seem to recall reading somewhere (perhaps in All American Boys) that they had to change ventilators due to the insufficient oxygen charge in them, but I'm not even sure where to start looking for that fact.

golddogMember

Posts: 176From: australiaRegistered: Feb 2008

posted 08-13-2009 10:29 PM
Thank you Mike, that was interesting reading, although the reference to removing their helmets refers to after the countdown demonstration test and not to the actual launch.

They would not have removed the helmets whilst being conveyed to the spacecraft for launch because the prebreathing exercise and use of pure oxygen throughout the suit circuit was designed to eliminate nitrogen from the blood stream, thereby limiting any chance of the bends.

To remove the helmets prior to launch would negate the whole process. It was for that reason that Walt Cunningham was reluctant to switch ventilators on Apollo 7.